HIGH-VALENT DIPHENYLACETYLENE COMPLEXES OF TUNGSTEN

Show simple item record

dc.contributor.author NIELSON, AJ en
dc.contributor.author Boyd, Peter en
dc.contributor.author Clark, George en
dc.contributor.author HUNT, PA en
dc.contributor.author HURSTHOUSE, MB en
dc.contributor.author Metson, James en
dc.contributor.author RICKARD, CEF en
dc.contributor.author SCHWERDTFEGER, PA en
dc.date.accessioned 2011-09-12T04:04:28Z en
dc.date.issued 1995-04-07 en
dc.identifier.citation Journal of the Chemical Society, Dalton Transactions 1153-1161 1995 en
dc.identifier.issn 0300-9246 en
dc.identifier.uri http://hdl.handle.net/2292/7895 en
dc.description.abstract The W(4f7/2) binding energy of [{WCl4(PhC2Ph)}2] 1 obtained by X-ray photoelectron spectroscopy is similar to that of [{WCl4(NPh)}2] and is consistent with a do tungsten(VI) formulation. The reaction of complex 1 and [NEt4][WCl5(PhC2Ph)] 2 with NaOH-EtOH gave cis-stilbene. indicating considerable electron transfer from the metal to the co-ordinated alkyne. Reduction of complex 1 with 2 equivalents of sodium-mercury amalgam in the presence of phosphines gave the complexes [WCl3(PhC2Ph)L2] (L = PMe3. PMe2Ph or PMePh2) with magnetic moments and W(4f7/2) binding energies similar to those of the d1 tungsten(V) organoimido complex [WCl3(NPh)(PMe3)2]. Decomposition of the alkyne complexes with NaOH-EtOH again gave cis-stilbene. The crystal structure of [WCl3(PhC2Ph) (PMe3)2] 3 has been determined. The W-Cl bond trans to the alkyne ligand is long [2.479(3) Å]. and the W-C bond lengths [2.011(13) and 2.038(12) Å] indicate a four-electron-donor alkyne ligand. The geometry is similar to that of [WCl3(NPh) (PMe3)2]. Reduction of [{WCl4(PhC2Ph)}2] using 4 equivalents of sodium-mercury amalgam in the presence of phosphines gave the complexes [WCl2(PhC2Ph)L3] (L = PMe3 or PMe2Ph) which again produced cis-stilbene on decomposition with NaOH-EtOH. The acetylenic carbon resonance at δ 223.15 in the 13C-{1H} NMR spectrum of [WCl2(PhC2Ph) (PMe3)3] 6 is also indicative of a four-electron-donor alkyne ligand. Its W(4f7/2) binding energy is similar to [WCl2(NPh) (PMe3)3] and is consistent with tungsten(IV). A crystal structure of complex 6 shows a similar ligand geometry to [WCl2(NPh) (PMe3)3]. and the W-C bond lengths [2.019(11) and 2.006(11) Å] indicate a four-electron-donor alkyne ligand. Hartree-Fock and scattered wave Xα calculations have been performed on the model complexes [WCl5(HC2H)]- 8. [WCl3(HC2H) (PH3)2] 9 and [WCl2(HC2H) (PH3)3] 10. Molecular orbital and population analyses indicated that the acetylene-tungsten bond in each involves W(5dπ) → HC2H(π*) back donation as well as HC2H(π) → W(5dσ) and HC2H(π⊥) → W(5dπ) forward donation. consistent with a four-electron-donor alkyne formalism. Electron withdrawal from the tungesten to the more electronegative Cl ligand in complexes 8 and 9 is minimised by rotation of the alkyne away from the meridional vectors. In complex 10 the HC2H(π⊥) → W(5dπ) donation and phosphine contributions compensate and no rotation is observed. The total d atomic orbital population of complex 8 is close to that of WCl6, and populations of complexes 9 and 10 step up linearly from this. The computational results support the experimental evidence that [{WCl4(PhC2Ph)}2] 1, [WCl3(PhC2Ph) (PMe3)2] 3 and [WCl2(PhC2Ph) (PMe3)3] 6 are complexes of tungsten-(VI), - (V) and - (IV) respectively. en
dc.language English en
dc.publisher ROYAL SOC CHEMISTRY en
dc.relation.ispartofseries JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.subject Science & Technology en
dc.subject Physical Sciences en
dc.subject Chemistry, Inorganic & Nuclear en
dc.subject Chemistry en
dc.subject ALKYNE-COMPLEXES en
dc.subject TANTALUM(III) COMPOUNDS en
dc.subject ORGANOIMIDO-COMPLEXES en
dc.subject MOLECULAR-STRUCTURES en
dc.subject CRYSTAL-STRUCTURE en
dc.subject MOLYBDENUM en
dc.subject NIOBIUM(III) en
dc.subject LIGANDS en
dc.subject ACETYLENES en
dc.title HIGH-VALENT DIPHENYLACETYLENE COMPLEXES OF TUNGSTEN en
dc.type Journal Article en
dc.identifier.doi 10.1039/dt9950001153 en
pubs.issue 7 en
pubs.begin-page 1153 en
dc.rights.holder Copyright: Royal Society of Chemistry en
pubs.author-url http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=A1995QT25300016&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=6e41486220adb198d0efde5a3b153e7d en
pubs.end-page 1161 en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype Article en
pubs.elements-id 141852 en
pubs.org-id University management en
pubs.org-id Office of the Vice-Chancellor en
pubs.record-created-at-source-date 2013-06-05 en


Files in this item

Find Full text

This item appears in the following Collection(s)

Show simple item record

Share

Search ResearchSpace


Browse

Statistics